Project Summary/Abstract The development of stem cell-based therapies for curing disease and restoring organ function has led to a critical need to identify endogenous stem cells and their regulators in craniofacial tissues. We have made significant inroads into deciphering stem cell identity and regulation in the salivary gland, a craniofacial organ system profoundly affected by chronic diseases (e.g., aging, autoimmunity, cancer) for which there are few symptomatic treatments and no long-term restorative therapies. However, despite progress in the field, we are still very much in the early stages of understanding the mechanisms driving organ repair and regeneration. Thus, based our previous studies revealing the identity and function of salivary progenitors and novel roles of cholinergic nerves in morphogenic and renewal programs, we seek to elucidate the mechanisms driving salivary gland regeneration by exploring 4 significant questions: (1) How do salivary stem cells enable organ renewal? (2) How do nerves control organ homeostasis and regeneration? (3) How does aging impact salivary stem cells? And finally, (4) How is salivary gland architecture created? We will answer these questions using a combination of developmental and regenerative approaches in mice and human tissue together with a bevy of molecular, biochemical, imaging and cell biological assays. Outcomes here will uncover novel cellular and molecular mechanisms required for the development of stem cell based therapeutics for reversing damage in these and other organ systems.